Patients who achieved long-term clinical complete response and subsequently terminated multidisciplinary and anti-HER2 therapy for metastatic breast cancer: A case series

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) -positive breast cancers tend to be more aggressive and more likely to recur than HER2-negative breast cancers. However, novel anti-HER2 therapies have dramatically improved the prognosis of patients with HER2-positive breast cancer. CASE REPORT: We review the cases of 4 women with metastatic breast cancer who achieved clinical complete response (cCR) and terminated their systemic therapy. Two patients had de novo metastatic disease and two patients experienced relapse after adjuvant therapy. All patients achieved cCR using multidisciplinary therapy, experienced prolonged complete remission, and subsequently terminated their systemic therapy without experiencing secondary recurrence. CONCLUSION: There is no evidence that systemic therapy can be safely terminated after a specific time period, although adverse events (e.g., cardiotoxicity) and unnecessary treatment should be avoided. Thus, it is possible that select patients may be suitable for termination of systemic therapy after they have achieved a prolonged period of cCR.